Commit a9018adf authored Oct 11, 2019 by Dan Carpenter Committed by Jason Gunthorpe Oct 22, 2019

RDMA/uverbs: Prevent potential underflow

The issue is in drivers/infiniband/core/uverbs_std_types_cq.c in the
UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE) function.  We check that:

        if (attr.comp_vector >= attrs->ufile->device->num_comp_vectors) {

But we don't check if "attr.comp_vector" is negative.  It could
potentially lead to an array underflow.  My concern would be where
cq->vector is used in the create_cq() function from the cxgb4 driver.

And really "attr.comp_vector" is appears as a u32 to user space so that's
the right type to use.

Fixes: 9ee79fce ("IB/core: Add completion queue (cq) object actions")
Link: https://lore.kernel.org/r/20191011133419.GA22905@mwanda


Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

parent 777a8b32

drivers/infiniband/core/uverbs.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -98,7 +98,7 @@ ib_uverbs_init_udata_buf_or_null(struct ib_udata *udata,

	struct ib_uverbs_device {		struct ib_uverbs_device {
	atomic_t refcount;		atomic_t refcount;
	int num_comp_vectors;		u32 num_comp_vectors;
	struct completion comp;		struct completion comp;
	struct device dev;		struct device dev;
	/* First group for device attributes, NULL terminated array */		/* First group for device attributes, NULL terminated array */

include/rdma/ib_verbs.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -366,7 +366,7 @@ struct ib_tm_caps {

	struct ib_cq_init_attr {		struct ib_cq_init_attr {
	unsigned int cqe;		unsigned int cqe;
	int comp_vector;		u32 comp_vector;
	u32 flags;		u32 flags;
	};		};

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